RICS Surveyor in France. Go ‘green’ with period property and ventilate, ventilate, ventilate!!!

As a RICS Surveyor in France, we see that one of the largest causes of damage and degradation to houses is caused by the presence of damp. This in turn creates the perfect environment for wood rot and wood boring insects that can cause a huge amount of damage to timber structures. Damp in masonry may cause spalling and degradation of stonework and ‘blowing’ of render, in addition to corrosion of steel reinforcing rods within concrete structures. As the steel rusts it expands and the concrete surrounding the steel becomes detached. This compromises the structural capability and ultimately leads to failure.

RICS Surveyor in France. 'blown' concrete around rusting reinforcing rods

RICS Surveyor in France. ‘Blown’ concrete around rusting reinforcing rods

As a RICS Surveyor in France we see particular examples of damp being introduced to buildings, often as a result of modern building materials and repairs being inappropriately applied to houses of traditional construction.

However, there is an enormous and ever increasing promotion of so called ‘energy saving measures’ that seek to reduce energy consumption and CO2 emissions from houses. Despite the degradation caused by damp, ironically these initiatives often promote the eradication of drafts with the installation of modern windows that seal without any air gap, the introduction of draft seals and huge amounts of insulation to lofts.  Whilst such advice is well intentioned, sadly the logic is flawed and counter productive when applied to traditionally constructed properties. The reason is that older properties often have solid stone walls and floors, without damp proof course or cavity. The design on construction was to allow the damp to escape from the house via gaps in windows and beneath doors and through vapour permeable materials. This allows the house to ‘breathe’ and remain dry. This in turn allows the house to remain free from wood rot and insect attack etc.  

RICS Surveyor in France. Modern window restricting ventilation

Modern window restricting ventilation

Even ignoring damp ingress through leaks etc, the production of water vapour can be huge from every day living including breathing, showers, cooking etc. From these every day activities, 4 occupants within a house will typically produce approximately 5 litres of water per day. So 150 litres of water carried within a much larger volume of air needs to be ventilated out of the house every month, otherwise water will be absorbed into the plaster of walls and timber joists etc. In addition of course the natural dampness from the ground, and building fabric needs to be extracted from the house.

RICS Surveyor in France. Ventilation

Damp air condensing on window. A similar process takes place to non-permeable materials within walls etc but is concealed from view.

Ironically the result of the ‘energy saving measures’ can result in reduced ventilation that in turn can result in degradation of the building fabric. This may then require extensive timber and other repairs to be needed. These repairs including the replacement materials are likely to result in the consumption of much more energy and production of more CO2 emissions than the ‘energy saving measures’ could ever have achieved. Furthermore, the financial cost of the repair works is likely to be significantly more than any perceived energy cost saving.

As a Surveyor in France, we understand the logic of traditional and modern construction methods. Our Surveys in France take account of the construction method adopted in the house. This will also influence our corresponding approach and advice as to ventilation. When undertaking RICS Surveys we also provide forward looking recommendations and care plans that will help keep the structure dry and thus naturally resilient to wood rot and insect attack, and also preserve the masonry. Accordingly the house will also be more environmentally sustainable. These principals will be valid at the date of the Survey Report and equally valid for generations to come.


Structural Survey in France. Traditional strategy to treat wood rot and provide future natural defence

Structural Survey in France – this brief summary presents the traditional strategy for the treatment and prevention of wood rot within buildings.  When undertaking a Structural Survey in France we adopt this approach in the recommendations. It is very similar to the approach for addressing wood worm.

The process of wood decay is an essential part of the ecosystem, converting dead wood into humus. Were it not for this process, the forest floor would be full of dead trees. Wood decay is achieved by a combination of wood boring insects and wood rot.

Structural Survey in France - wood rot

Damp resulting in wood rot.

As the rot develops, it softens the timber allowing it to absorb more moisture. This makes it an attractive environment for wood boring insects that will further degrade the timber. Left unchecked, the rot will develop and compromise the structural capability of the timber. This may lead to full structural failure. Remedial work may be very expensive and disruptive if replacement timber is required, especially if the timber is recessed behind masonry and plaster etc.

There are 2 key types of fungal attacks to wood, namely wet rot and dry rot. Both require elevated levels of moisture to be present in the wood in order to survive. However, dry rot requires less moisture to be present so is sometimes of more concern as it can flourish and quickly spread even in less damp conditions.

If the wood is dried to adequate levels (through addressing the source of the damp, combined with ventilation), existing rot will die in the drying process. Importantly the dried wood will become an unattractive environment for future fungal attack and naturally resistant to future attack.

When undertaking a Structural Survey in France, in addition to reporting any damp issues that may be present, we also detail remedial options including repair works and modifications to address damp. We also provide care plans such as increasing ventilation, particularly in loft space where ventilation may be compromised. This will allow the overall structure to remain dry, including of stone walls that in turn will draw moisture away from timber embedded within the wall.

An alternative approach to combat wood rot is to use modern chemical treatments. However, some timber may be inaccessible to treatment, for example concealed behind masonry or plaster. Where chemical treatment is recommended, this should always be undertaken in tandem to addressing any damp issues, with the objective of drying all areas.

We are firm believers in the traditional approach of keeping the structure dry to effectively combat wood rot, and importantly provide a natural defence for the future. This approach is centuries old in the making will last for centuries to come.


Strategic approach to combat termites in France

The following blog summarises the strategic approach to combat termites in France.  As a Building Surveyor in France we adopt this approach when undertaking surveys.  Termites are small insects that feed upon the cellulose of wood. There are 7 species found in France, most prominently in the South West albeit they are expanding info further areas as the climate warms. They live in sophisticated colonies organised into various specialist teams that gives them the ability to destroy timber structures with alarming speed and efficiency. Furthermore, because they devour the timber from within the timber structure, their presence and destructive work may go unnoticed for years. Timber beams may look sound, but have been hollowed out by the termites. This results in weakening the timber or total structural failure.

Termites are therefore of concern to both homeowners and the French authorities. The law in France requires that when selling a house the vendor is required to commission a report within the DDT that confirms the presence / absence of termites. The report is valid for a period of 6 months and is not qualified to comment on the structure of the house nor the specific consequences of infestation to the particular elements of the building structure.

The modern approach to address infestations includes replacement of damaged wood the application of chemicals to the deter future attack. However, much of the infestation will be in the timber favoured by the termites, buried deep behind masonry and therefore inaccessible to treatment. Accordingly remediation can be very costly and disruptive.

As a Building Surveyor in France we provide advice to adopt a strategic approach to combat termites and importantly provide enhanced defence against future infestation. To better understand the approach, it is important to firstly understand the environment required by termites. Subterranean termites require a damp environment in which to live and avoid sunlight. They build mud tubes to allow them to travel over dry structures and remain concealed from bright light. Accordingly a key to providing a less attractive environment to termites is the removal of damp to the structure and timber within the building. This is normally undertaken by a combination of addressing faults to roofs, gutters, drainage etc in addition to ensuring adequate ventilation to floor voids, roof voids etc. It is important that humid air from within the living areas of the house is ventilated out of the house and not into the roof void. Removal of shrubs and debris etc around the base of the house will also reduce shading and allow for easier inspection and observation of any termite evidence.

‘Dry wood’ termites nest above ground and don’t require contact with the ground. Like any organism, even ‘dry wood’ termites require some moisture to live that they derive from the wood.

As a Building Surveyor in France, we undertake detailed Property Survey inspections in accordance with RICS training and standards. This includes damp meter readings to timber and masonry. The Survey Report is forward looking, providing recommendations as to how to maintain and ventilate the property so as to keep the structure dry. This in turn will draw moisture away from timber imbedded within stone walls etc. The Survey also includes outbuildings and the general garden / grounds surrounding the house. Specific recommendations are made as to the type of plants / shrubs and flower bed design that should be adopted in the area surrounding the house so as to provide a hostile environment for termites. This is a critical element of the overall measures to be adopted to enhance defence to combat termite infestation. The vendor’s DDT report is valid for 6 months and is understandably caveated by the fact that the inspection cannot assess timber that is inaccessible, including that concealed behind masonry. The principles of our Report recommendations are valid for decades, and include recommendations for the drying of even the concealed timber. 


RICS Surveys in France. Traditional roof construction in France

When undertaking an RICS French property survey, we see that many UK buyers tend to favour period properties either for permanent occupation or for holiday homes. When first viewing the loft space within French properties, many buyers are often concerned to see a vast array of bright spots of sunlight piercing the gaps between tiles. Furthermore, buyers may be concerned not to see felt under the tiles as is common practice in UK construction. Their immediate response is often of alarm, with concerns as to rain water cascading through the gaps, drenching everything beneath.

Often such concerns may be put to ease. To understand why, an understanding of the construction methodology is needed. It is common in France for felt not to be laid beneath the tiles, thus the underside of the tiles is exposed. The bright spots of daylight are normally via light penetrating laterally through spaces between the tiles. Clearly checks have to be made as to whether any are capable of water ingress.

No felt beneath battens allowing inspection of battens and underside of tiles.

No felt beneath battens allowing inspection of battens and underside of tiles.

The advantages of the traditional French approach of not using felt underlay include the following:

  • The roof will benefit from improved ventilation. The air within the loft is usually warmer than the outside air, so will naturally rise up through the gaps. This draws moist air away from the house beneath, and allows ventilation to the roof joists / rafters, and battens upon which the tiles are mounted
  • The underside of the tiles and battens are not obscured by felt and can be inspected to assess their condition. It also can allow for the replacement of individual broken tiles from within the loft, by carefully raising the adjoining tiles. This may be important where exterior access may be restricted by height that may require scaffold etc
  • If a leak does exist, the precise location of the leak can often be seen from within the loft thus facilitating repair. If the leak were onto a felt membrane, the water would then travel over the felt, often travelling horizontally for some distance having being diverted by the horizontally fitted battens. This makes identification of the precise location of the leak difficult. The felt would also direct the water to the underside of the battens making them prone to rot.
  • The absence of the felt results in a reduced weight that would otherwise be carried by the roof structure.

As a Chartered Surveyor when undertaking a detailed RICS French Property Survey we understand the logic of both traditional and modern construction. Our detailed Survey Reports understand the ethos of the architecture and construction techniques. We also provide Care Plans to allow you to adopt the correct approach to maintenance taking account of the construction.  The approach to maintenance of traditional and modern buildings is necessarily very different. Armed with the French property survey report and Care Plans you can significantly reduce future maintenance and repair costs.

Building Survey in France. Property Maintenance – a forward looking approach

Building Survey in France. Property Maintenance – a forward looking approach 

A Building Survey in France is of real value not only to allow informed decisions in the buying process, but also for existing homeowners. The Building Survey allows for a logical and planned approach to your Property Maintenance in France.

Properties are often presented to the market with statements within the details such as ‘in good condition’ although the qualification and basis upon which such statements are made is often questionable. A detailed inspection of concealed joists deep within the roof void or floor void can often tell a very different storey!

The Building Survey Report details defects and wants of repair with remedial options. This will then allow for an assessment of budget costs and consideration within the overall purchase with informed decision making.

Importantly when undertaking a Building Survey in France we undertake a detailed inspection to assess:

  • The current condition and wants of repair. This will allow for informed decisions to be made within the buying process
  • The anticipated future position in years to come taking account of matters that are developing or run the risk of so doing.

Both of the above points are critical. However, the second point is really valuable in terms of allowing for a Planned Maintenance Programme to be adopted. For example, there may be a situation where there is compromised ventilation to a floor void. As a result, the timber within the void might currently be showing early signs of decay or insect attack. Early intervention by way of enhancement of ventilation can arrest the position at an early stage rather than allowing it to develop and then require a significantly more expensive and disruptive repair. It is often the implementation of very simple modifications and Planned Maintenance that can avoid the need for future costly and disruptive repair works. “A stitch in time…”

Accordingly the Building Survey Report provides real value now in respect of providing information upon which informed decisions can be made in the buying process. The survey report also provides value to the future by way of reduced repair and maintenance costs. The report can be tailored so as to provide a Planned Maintenance Programme (PMP) for your house, allowing works to be undertaken in logical sequence. This will also reduce disruption and allow for phased budget planning. All too often we see examples of property maintenance that has focussed on particular areas such as external decoration of windows and yet no maintenance has been undertaken within the roof void where often much more costly remedial work may be required unless maintenance is undertaken. For this reason a Survey Report is also of real value in respect of a house that you already own, providing a Planned Programme for your Property Maintenance in France. The Building Survey Report can be sent by pdf or hard copy.

Building Survey in France.

Building Survey in France. Report issued in bound hard copy or emailed as pdf file.



English speaking Surveyor in France. Property maintenance

The correct property maintenance and repair is essential to allow for reduced costs over time. As an English speaking surveyor in France, we undertake RICS surveys for clients wishing to buy properties and also for existing homeowners with recommendations for planned property maintenance programmes.

We are increasingly seeing defects that are of significant scale often concerning large areas of the house fabric. These defects are not due to the normal passage of time and lack of maintenance. Ironically the defects are increasingly being caused by inappropriate maintenance undertaken with materials that are totally inappropriate particularly when applied to traditional structures.

For example, the solid walls of traditional buildings were designed to be vapour permeable. Whilst this will allow some rain to soak into the wall, critically the damp will also be drawn from the wall by evaporation. So the house is able to ‘breathe’. This will have allowed the wall to remain in a balanced state of low moisture content for decades. This in turn will have drawn moisture away from structural timber joists embedded deep within the wall. By keeping the joist ends dry, they will have remained free from wood rot and infect infestation for decades.

However, we are now increasingly seeing the inappropriate use of modern non breathable paints and cement based mortars incorrectly being applied to these structures. These materials will inevitably allow some moisture ingress. However this moisture and indeed that generated from within the house is not then able to escape by evaporation. It’s like wrapping the house cling film!

English speaking surveyor in France. Masonry paint trapping moisture

Modern ‘non breathable’ masonry paint trapping moisture within a brick wall. Note the ‘blistering’ as the moisture tries to escape.

Accordingly the damp builds up within the walls over time allowing the degrading of wood from rot and insect attack. Damp masonry also degrades, with the damp causing corrosion of steel reinforcing rods and ‘blowing’ of render. The house will also feel damp and cold, often then resulting in increasing heating bills.

It is important to have a property survey to professionally advise as to the logical sequence of works and correct use of materials. As an English speaking Surveyor in France, we not only assess and report on the current condition. We can also provide planned property maintenance programmes with the correct materials and paints so as to save you falling into the trap of having works done that are actually doing more harm and promoting the degradation of the structure.